Intensive therapy is now accepted as the current standard of care in diabetes. However, intensive therapy is frequently complicated by hypoglycemia, which then becomes a limiting factor in maintaining glucose control. During intensive treatment, hypoglycemia occurs in patients with diabetes due to excess insulin, 'excess glucose utilization (e.g. exercise) or inadequate carbohydrate intake. Young children and adolescents have many lifestyle characteristics that make them particularly prone to hypoglycemia. In addition, frequent hypoglycemia may lead to neurological sequelae. With current home glucose monitoring capabilities it is difficult to accurately define the true incidence, duration and severity of hypoglycemia. Continuous glucose monitoring (CGM) has recently become available as a tool to more closely examine glucose patterns and defining characteristics of hypoglycemia, so that measures for prevention of hypoglycemia can be devised. Recent neurocognitive and neuro-imaging studies show that the developing brain may be particularly vulnerable to hypoglycemia. The understanding of specific neurocognitive deficits requires further studies in children and young adults. Optimal prevention of hypoglycemia and its sequelae requires near-continuous recognition and response to prevailing blood glucose concentrations. Hence, our major objective is to use CGM to detect the frequency, severity and duration of hypoglycemia and then carry out a randomized controlled trial (RCT) to determine the ability of real-time CGM to minimize the risk of hypoglycemia in young patients with type 1 diabetes (T1DM) ages 7-24. In addition we will examine added variables of intervention with activity assessment, diet or both, to determine if further reductions in hypoglycemia are achievable. At baseline, we will compare rates of hypoglycemia frequency, severity and duration and other factors, such as age at onset or duration of diabetes, with neurocognitive and neuroimaging parameters in a cross-sectional study. We will characterize neuroanatomical differences in children and young adults with T1 DM, vs. normal controls. Our center has participated in the Diabetes Research in Children Network (DirecNet), a successful, NIH funded consortium of 5 pediatric diabetes centers and a coordinating center established to study hypoglycemia in children with T1 DM. We have excellent infrastructure, trained personnel, a highly efficient system of patient recruitment, and successful history of efficient protocol completion.